Method for forming tubular articles



March 17, 1953 G. s. WHYTLAW METHOD FOR FORMING TUBULAR ARTICLES Filed July 18, 1944 INVENTOR.

ATTORNEY Patented Mar. 17, 1953 METHOD FOR FORMING TUBULAR ARTICLES Graeme G. Whytlaw, Swarthmore, Pa., assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware Application July 18, 1944, Serial No. 545,504

3 Claims.

This invention relates to the production of a continuous tubular article from a flat sheet. It is particularly concerned with the production of tubes of paper for wrapping wound packages of textile materials, such as rayon cakes, cones, or the like, preparatory to liquid treatment of such wound packages. However, it is applicable as well to the formation of tubes from a sheet or web of paper, textile fabrics, metal foils, or other flexible materials for any use or purpose whatsoever.

In accordance with the present invention, a sheet of a flexible material is guided so that one of its lateral edges is lapped over the opposite lateral edge to form a hollow tube; if the sheet is thermosensitive or if it contains thermosensitive fibers, the overlapped portions are subjected to heat and pressure tocement the joint; otherwise a narrow strip or thread of a thermosensitive material is directed between the overlapped portions of the material and these portions are then subjected to heat and pressure to cement the lapped joint. The invention is of special advantage when specifically modified for the continuous production of tubular articles.

In the drawing which is illustrative of the invention- Figure 1 is a plan View of a preferred embodiment of apparatus for practicing the invention;

Figure 2 is a cross-section on line I[-II of Figure 4;

Figure 3 is a side elevation; and

Figure 4 is a bottom view of one of the guiding elements of the apparatus of Figure 1.

As shown in Figures 1 and 2, the apparatus comprises a supply roll 2 for a continuous sheet of the flexible material to be formed into a tube, which, in the specific instance herein described, happens to be paper. From the supply roll, the paper 3 passes between slitting mechanism which may comprise two rolls 4 and 5, one or both of which is provided with suitably arranged knives 6 to slit the paper longitudinally with parallel rows of slits '7, so that those in any one row are offset from those in the next adjacent row. The rolls 4 and may be driven by means (not shown) suitably synchronized with the take-up.

The paper sheet 3 passes over the controlling guide 8 (more particularly shown in Figures 3 and 4) and into the forming guide 9 into which the guide 8 partially extends generally concentrically but spaced from the internal surface a sufflcient distance to form an annular passage for the flexed sheet. The forming guide 9 is supported by the bracket 19 and is of substantially cylindrical shape except at its entrance, which is flared outwardly. The guide 8 is supported by the bracket H and has a portion 12 of one edge lapped over but spaced from the opposite inturned edge portion [3. Beyond the edge portion l2, this edge is cut away as at 14 and the edge portion l3 gradually flares outwardly, so that the guide 8 has a substantially cylindrical cross-section at line AA of Figure 4. At the bottom of the exit ends of the guides 8 and 9 there are provided slots l5 and I6 respectively.

A heated rotatable drum or roll I! is mounted in proximity with the aligned slots [5 and I6, and a pressure roll l8 rides on top of the drum l1, being supported by a pivoted arm [9 urged downwardly by the spring 20.

A thread or narrow strip 2| of thermosensitive material passes through a tensiondevice 22 and a guiding pulley 23 and between the overlapped edge portions of the flexible sheet as shown in Figure 3, until it finally passes between the rolls I? and I8 Where the heat and pressure render it adhesive to bond the overlapped edges of the sheet 3, thereby forming the tube 3A which proceeds under a bail or rod 24 and to the take-up 25 which may be rotated by any suitable means (not shown).

While the apparatus as shown includes the slitting device 4, 5, this may be omitted entirely, or it may be arranged between the discharge side of the guides 8 and 9 and the take-up 25. For certain purposes it may be desired to replace such means with a perforating means. If the sheet of flexible material to be formed into a tube contains fibers of a thermosensitivematerial, the means for supplying a strip of material 2| may be omitted.

The thread or strip 2| may be composed of any material thermoplastic or even thermosetting which is rendered adhesive by heating. Examples of such materials include the vinyl resins, particularly those of polyvinyl chloride, copolymers of vinyl chloride with vinyl acetate or acrylcnitrile, after-chlorinated vinyl polymers or copolymers, polyvinylidene chloride; also acrylic and methacrylic acid ester resins, such as polymerited methyl methacrylate; nylons; cellulose derivatives, such as ethyl cellulose and so on.

The present invention has numerous advantages in that the messiness that accompanies the application of liquid adhesives is entirely avoided. The strip 2! is readily controlled reliably, so that itcannot escape from its relationship between the overlapped edge of the sheet to be bonded before its activation to an adhesive condition. In addition, the use of a narrow continuous thread or strip provides a simple way of controlling the amount of adhesive and the width of bonding layer in the product, which makes it possible to limit the change in liquid permeability of the bonded areas of the sheet to a minimum, or to control it to provide any predetermined change in permeability, depending upon the ultimate use to which the product is intended to be put.

The invention is of special advantage when applied to the production of liquid-permeable paper wrappers for wound cakes of rayon resulting from the collection of freshly spun filaments in centrifugal buckets. Such wrappers and their use is disclosed and claimed in the copending application for United States Letters Patent of Decker and Spangler, Serial-No. 508,526, filed October 16, 1943 now Patent 2,382,400. After the tubular wrapper is collected on the take-up 25, it needs merely to be cut to the desired length to provide the final wrapper of sleeve-like form.

It has also been found that the paper sheet should be slit longitudinally of the grain of the paper, which should lie parallel to the axis of the tube. It has heretofore been the practice, when ever slitting of thin paper has been resorted to for any purpose, to orient the slits across the grain of the paper, because this had always been thought necessary to produce satisfactory products. Surprisingly, it has been found that, for the purpose of wrapping rayon cakes to protect the windings during liquid treatment, the slits should be made in the direction of the grain of the paper. Otherwise, it has been found, the development during liquid treatment of a tear extending between two adjacent rows of slits will rapidly extend progressively across several of the adjacent rows and frequently across the entire wrapper. Such tears do not grow in this fashion when the slits are oriented in the direction of the grain of the paper, but stop by the time they reach across the space between two adjacent rows of slits.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims. In the claims, the term strip is intended in a generic sense to comprehend monofilament or multifilament threads as well as ribbons or bands of slight or considerable width. Similarly, tubular and tube is not to be restricted to a hollow cylindrical article, but may include a hollow article of any cross-section.

Iclaim:

1. A method of forming a tubular article from 4 a flexible sheet of paper having a grain extending in one direction thereof comprising providing the sheet with parallel rows of staggered slits parallel to the grain thereof, lapping one edge of the sheet parallel to the grain over the opposite edge thereof to form it into tubular shape, placing a strip of thermosensitive material between the overlapped edges, so that it extends longitudinally thereof, and activating the strip to an adhesive condition to bond the lapped edges together.

2. A method of forming a tubular article from a flexible sheet of indefinite length comprising continuously delivering the sheet from a supply thereof through a path, slitting the sheet with parallel rows of staggered slits, lapping one lateral, edge of the continuously moving sheet over the opposite lateral edge thereof, continuously drawing a strip of thermosensitive material between the overlapped edges, and then subjecting the overlapped edges with the strip therebetween to heat and pressure.

3. A method of forming a tubular article from a flexible sheet of paper of indefinite length having a longitudinal grain comprising continuously delivering the sheet from a supply thereof through a path, slitting the sheet with parallel rows of staggered slits parallel to the grain thereof, lapping one lateral edge of the continuously moving sheet over the opposite lateral edge thereof, continuously drawing a strip of thermosensitive material between the overlapped edges, and then subjecting the overlapped edges with the strip therebetween to heat and pressure.

GRAEME G. WHYTLAW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,094,427 Cook Apr. 28, 1914 1,215,464 Armstrong Feb. 13, 1917 1,824,285 Matson Sept. 22, 1931 1,987,596 Cox Jan. 15, 1935 2,060,906 Snyder Nov. 1'7, 1936 2,144,899 Smith Jan. 24, 1939 2,145,636 Scharf Jan. 31, 1939 2,148,884 Walter i Feb. 28, 1939 2,169,936 Wagner Aug. 15, 1939 2,285,263 Fitch June 2, 1942 2,335,159 Salfisberg Nov. 23, 1943 2,364,903 Howard Dec. 12, 1944 2,384,462 Goodman Sept. 11, 1945 

